Overload relief for conveyer systems



Dec. 12, 1933. N. H. PREBLE 1,938,720

OVERLOA'D RELIEF FOR CONVEYER SYSTEMS Filed July 28, 1930 Wbrman ll. 'rcble ATTORNEYS V INVENTOR Patented Dec. 12, 1933 ovnar-oan REIJEF FOB CONYEYER svs'rrms Norman 11. Preble, Detroit, mm, amignor a Mechanical Handling Systems, Incorporated, Detroit, Mich a corporation of Michigan Application July 28, 1930. Serial No. 11,324

3 Claims. (Cl. 192-116.5)

The invention relates to conveyer systems and consists in the novel construction of overload relief for preventing over-stressing or breakage as hereinafter set forth.

In the drawing:

Figure 1 is a plan View of the overload relief mechanism;

Figure 2 is a side elevation thereof;

Figure 3 is a sectional view taken substantially on theline3 -3ofFigure 1. I

My relief device may be applied at any vsui able point in the power transmission to the conveyer system but as specifically illustrated it is arranged in connection with a worm gearing which drives the conveyer chain. Thus as shown inFigureLAisthewornl gearandBisthe worm for actuatim the same. these partsbeing enclwed in a suitable housing C. D is the worm shaft and E is a sprocket wheel mounted on said shaft and forming the driving means therefor.

The sprocket wheel E is rotatively mounted upon a sleeve F keyed on the shaft D and is 'normally coupled to said sleeve by a clutch.

This clutch is formed by'a cam face G on the hub of the sprocket E and a correspondingly cam face H upon a collar l. longitudinally slidable upon said sleeve and spiined thereto as indicated at J. The collar I is normally under the pressure of a spring having an adjustable abutment L threaded upon the sleeve F. 'Ihus by adjusting this collar L the spring may be suitably tensioned so that under normal mm the cams H and G will remain in engagement and will'thereby couple the sprocket E to the shattD. I.f,however,themechanisr nis overloaded thetorqueresismneeofthesprocketls willcausethecamGtorideoverthecamH preventing independent movement of the sprock- 40 et wheel E. I To stop further movement of the drive mechanism upon thedechltching of the sprocket E, there is arranged an electric switch which is actuated by the movement of the I. As shown,abellcrankleverMhasarollel-M' on 'one arm thereof which bears against a flange I onthecollarl. The otherarmofthebell cranklllsprovidedwithadetentllwhichis 'normallylnengagementwitbahookedannll ofanelectricswitchO. 'Ihisswitchmaybeot -anysuitableconstructlonbutisshovvnasoom- 'prlsingamovable bridge contactmemberP normallyconnectlngthecontacts QandQ'. "I'heimulatorboseP'ottbismovablecontact memberlsslkhblymounteduponguidslland is under the tension of a spring R; tending to move the bridge away from the contacts Q and D Q and into engagement with contacts Q, Q. This movementis normally prevented by the hooked member N engaging the detent M but 00 whenever the cam G in cooperation with the cam H forces the collar I against the tension of the spring K the detent ll will be disengaged from the hooked member N permitting the spring R to move the bridge contact P breaking the electric circuit S and establishing an electric circuit '1'. The circuit S is connected by a suitable relay (not shown) to a power switch which controls the motor or other driving means for. the sprocket E while the circuit T when 70 established operates an indicator which shows the operation of the overload relief. Thus the attendant can correct the abnormal condition whereupon the .mechanisn may be again started to perform its normal functions. 55

What I'claim as my invention is:

1. In a device of the class described, the combination with driving and driven members, of a clutch establishing an operative connection be tween-the driving and driven members and auto- 8 matically movable to disengage the said members .upon overloading the system, an electric circuit for transmitting power to the driving member.

a. switch for controlling the electric circuit, resil- 4 ient means for normally urging said switch to its 35 inoperative position wherein said circuit is open, a bell crank lever having one arm detachably engaging the switch-to hold ile same in its operative position against the action of said resilient means and having the other arm positioned to be actuated by the clutch upon movement of the latter to disconnect the driving and driven members for the first-mentioned armfrom the switch and thereby permitmovement of the latter to its inoperative position.

2. In a convent system, the combination with driving and driven members, of a clutch establishing a driving between the members and automatically operable to disengage he .members upon overloading the system, an elec- 1 tric circuit for transmitting power to the driving member, a second electric circuit for actuating =adevioetoindicatetbeoverloadoonditionoftbe systemgaawitchiorcontrollingbothotsaid. circuits, mm normally holding-said switch in apositionwhereinthesamefunctiomtoclose theflrstmentlonedcircult,yieldablemeamtendingtourgesaidswitchtoclosemidsecond'circutbandmeamcontrolledbytbeoperatlonot and clutch members rmmung said are:

2 named meansto pei'mif bfsaidyield- 3.Inaoonveyersystan,thecombimtiohwith --drivigmanddrivenmembers,ofaclutchestahbersahdantomaticallyopembletodisenzasethelishingadrlvingcunnectionbetweenthememother to open the latter circuit and cmethe auxiliarycircnit, meansnormallyretainingsnidswltch'inapositionwhemintbe flrstcimfltisclomyieldsble meanstendin: toumethgswitchjoapositionwherejnmid auiliary circuitisclmandmeans automaticallyopembleupondisengagementoftheclutch' munbersforactlmtingthefirstnamedmems topermittheoperationotsaidyieldablemeam.

NORIAHEPRIBLE. 

